14 October 2013

The Coastal Storm That Never Ends

Posted by Dan Satterfield

Here on the Delmarva, we’ve had 4 days of rain and a lot of it. Over 4.6 inches here in Salisbury, but parts of Delaware have had well over 6 inches. The wind hasn’t been anything like Sandy, or even a strong nor’easter, but it’s been blowing steady at 20-35 mph for four days!

Ctsy. NWS (Philadephia)/Mt. Holly NJ. Click for full size.

Ctsy. NWS (Philadephia)/Mt. Holly NJ.
Click for full size.

Waves and tides are affected by three factors however.

1.Wind Speed (How high are the winds)
2.Duration ( how long the strong winds blow)
3.Fetch (distance on the water the wind blows over).

In this case the wind speed is moderate, but the fetch and the duration are both very high. The result is that there has been significant beach erosion and high seas. How much of the beach re-nourishment project just finishing up on the coast of Delaware has been lost remains to be seen.

The storm seems to be ending and we may actually see some sunshine Monday. Much of the region has endured a significant dry spell, but that is just a memory now. It’s worth remembering that this same storm 50 years from now will cause significantly more erosion and coastal flooding, because the sea will be about 5-8 inches higher. We were just below the threshold of significant disruption this weekend. We’ll be well above it in a similar storm a few decades from now.